Mystery Bearing-like Noise

[Dan Weber]

Hey all,

I’ve got a noise I’m having trouble pinning down in my 2010 outback. Figured I’d try asking the internet before I replace all my wheel bearings on a hunch.

Between 60 and 65mph I’ve got a whomp-whomp-whomp noise at maybe 2 Hz that sounds a lot like a wheel bearing. It gets a bit louder and faster with speed, but fades into a general “background noise” above 65mph with no more audible pulsating. It does not seem to disappear as I turn in either direction, and when riding as a passenger I’m not able to tell that it’s louder if I stick my ear down by any of the wheel wells.
I jacked up the car, and felt for play or grinding on all four wheels and felt none. When I put the car in drive while jacked up and let the wheels spin, none had any low frequency noise, just what I would guess is light brake pad rubbing (say 800 grit sandpaper on a metal pipe). The driver side rear wheel barely turned, but on further inspection, the slide pin was locked up.
Changing “gears” with my CVT at 60mph doesn’t seem to get rid of the sound, nor does uphill / downhill driving. The noise does seem to go away occasionally during my highway tests, but I’m guessing that I’m just momentarily falling out of the 60-65mph sweet spot.

Any other advice on troubleshooting? Otherwise, I might just be replacing one wheel bearing at a time until it goes away.

-Dan

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